linux_dsm_epyc7002/arch/s390/kernel/vdso64/clock_getres.S
Martin Schwidefsky b7eacb59cd s390/vdso: add vdso support for coarse clocks
Add CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE optimization to
the 64-bit and 31-bit vdso.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-09-09 08:53:27 +02:00

53 lines
1.3 KiB
ArmAsm

/*
* Userland implementation of clock_getres() for 64 bits processes in a
* s390 kernel for use in the vDSO
*
* Copyright IBM Corp. 2008
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License (version 2 only)
* as published by the Free Software Foundation.
*/
#include <asm/vdso.h>
#include <asm/asm-offsets.h>
#include <asm/unistd.h>
.text
.align 4
.globl __kernel_clock_getres
.type __kernel_clock_getres,@function
__kernel_clock_getres:
.cfi_startproc
larl %r1,4f
cghi %r2,__CLOCK_REALTIME_COARSE
je 0f
cghi %r2,__CLOCK_MONOTONIC_COARSE
je 0f
larl %r1,3f
cghi %r2,__CLOCK_REALTIME
je 0f
cghi %r2,__CLOCK_MONOTONIC
je 0f
cghi %r2,__CLOCK_THREAD_CPUTIME_ID
je 0f
cghi %r2,-2 /* Per-thread CPUCLOCK with PID=0, VIRT=1 */
jne 2f
larl %r5,_vdso_data
icm %r0,15,__LC_ECTG_OK(%r5)
jz 2f
0: ltgr %r3,%r3
jz 1f /* res == NULL */
lg %r0,0(%r1)
xc 0(8,%r3),0(%r3) /* set tp->tv_sec to zero */
stg %r0,8(%r3) /* store tp->tv_usec */
1: lghi %r2,0
br %r14
2: lghi %r1,__NR_clock_getres /* fallback to svc */
svc 0
br %r14
3: .quad __CLOCK_REALTIME_RES
4: .quad __CLOCK_COARSE_RES
.cfi_endproc
.size __kernel_clock_getres,.-__kernel_clock_getres